KR101652848B1

KR101652848B1 - Coil component and method of manufacturing the same

Info

Publication number: KR101652848B1
Application number: KR1020150012734A
Authority: KR
Inventors: 박승욱; 김광모; 심원철
Original assignee: 삼성전기주식회사
Priority date: 2015-01-27
Filing date: 2015-01-27
Publication date: 2016-08-31
Also published as: US20160225513A1; JP6532387B2; JP2016139785A; US9972430B2; KR20160092290A

Abstract

The present invention provides a coil component including a magnetic substrate, an insulating layer provided on the magnetic substrate and having a coil conductor formed therein, and a reinforcing layer provided on the insulating layer and having a thermal expansion coefficient lower than that of the insulating layer do.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a coil component,

The present invention relates to a coil component, and more particularly, to a coil component that operates as a noise filter and a method of manufacturing the same.

As technology develops, electronic devices such as mobile phones, home appliances, PCs, PDAs, and LCDs are changing from analog to digital, and the speed is increasing due to an increase in the amount of data to be processed.

As a result, USB 2.0, USB 3.0 and high-definition multimedia interface (HDMI) have been widely used as high-speed signal transmission interfaces, and these interfaces are currently used in many digital devices such as personal computers and digital high- .

These high-speed interfaces employ a differential signaling system that transmits a differential signal (differential mode signal) using a pair of signal lines unlike a single-end transmission system that has been used for a long time. However, since the electronic devices which are digitized and accelerated are sensitive to external stimuli, signal distortions due to high frequency noise often occur.

In order to eliminate such noise, a filter is installed in an electronic device. In particular, a common mode filter is widely used as a coil part for eliminating common mode noise in a high-speed differential signal line and the like.

Common-mode noise is the noise that originates in the differential signal line, and the common-mode filter removes common-mode noise that can not be eliminated by existing filters.

In recent years, as frequency used in electronic products has increased, a common mode filter having improved narrowband characteristics and attenuation in a high frequency band has been required. That is, narrowband characteristics of about ± 25% to ± 20% based on the common mode impedance of 90Ω and high attenuation characteristics of -30 dB or more in the several Ghz band are required.

Accordingly, a common mode filter having a structure in which a coil layer is directly exposed to air without a separate magnetic member such as a ferrite-resin composite layer is proposed in order to minimize magnetic loss.

However, in this case, there arises a problem that the solderability of the parts due to shorting occurs during the soldering process for component mounting.

Further, a deviation occurs in the thermal expansion coefficient between the member constituting the common mode filter, for example, between the magnetic substrate and the insulating layer in contact with the common substrate, and deformation such as warpage occurs.

Patent Document 1: Japanese Laid-Open Patent Application No. 2005-129793

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coil component and a method of manufacturing the same, which have improved durability and improved mounting performance and which do not cause defects such as warpage.

According to an aspect of the present invention, there is provided a magnetic circuit comprising a magnetic substrate made of sintered ferrite, an insulating layer provided on the magnetic substrate and having a primary coil and a secondary coil formed therein, And a reinforcing layer having a thermal expansion coefficient lower than that of the insulating layer.

Here, the reinforcing layer may be a nonmagnetic polymer resin, or a mixture in which an inorganic filler such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ) and titanium oxide (TiO ₂ ) is dispersed in the polymer resin have.

The present invention also provides a coil component provided on an outer surface of an upper portion of an insulating layer for external electrical connection with the outside, or on a side surface of a laminate composed of a magnetic substrate, an insulating layer, and a reinforcing layer.

Here, when the external electrode is provided on the outer periphery of the upper part of the insulating layer, the reinforcing layer may be inserted into the empty space between the external electrodes.

According to the coil component of the present invention, it is possible to improve the mounting property together with the high attenuation characteristics, and the deviation of the thermal expansion coefficient between the components is alleviated, whereby defective products such as warpage can be suppressed.

1 is a perspective view of a coil component according to the present invention;
2 is a sectional view taken along line I-I '
3 is a cross-sectional view taken along the line II-II '
4 is a perspective view of a coil component according to another embodiment of the present invention.
FIG. 5 is a flowchart illustrating a method of manufacturing a common mode filter according to the present invention,

The advantages and features of the present invention and the techniques for achieving them will be apparent from the following detailed description taken in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The present embodiments are provided so that the disclosure of the present invention is not only limited thereto, but also may enable others skilled in the art to fully understand the scope of the invention.

The terms used herein are intended to illustrate the embodiments and are not intended to limit the invention. In this specification, the singular forms include plural forms unless otherwise specified in the text. Further, elements, steps, operations, and / or elements mentioned in the specification do not preclude the presence or addition of one or more other elements, steps, operations, and / or elements.

On the other hand, the constituent elements of the drawings are not necessarily drawn to scale, and for example, the sizes of some constituent elements of the drawings may be exaggerated relative to other constituent elements to facilitate understanding of the present invention. Like reference numerals refer to like elements throughout the drawings, and for purposes of simplicity and clarity of illustration, the drawings illustrate a general manner of organization and are not intended to unnecessarily obscure the discussion of the described embodiments of the present invention Detailed descriptions of known features and techniques may be omitted so as to avoid obscuring the invention.

Hereinafter, the configuration and operation effects of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a coil part according to the present invention, FIG. 2 is a sectional view taken along line I-I 'of FIG. 1, and FIG. 3 is a sectional view taken along a line II-II' of FIG.

1 to 3, a coil component 100 of the present invention includes a magnetic substrate 110, an insulating layer 120, and a reinforcing layer 130.

The magnetic substrate 110 is a plate-shaped support formed of a ceramic material, and is disposed at the lowermost portion. The insulating layer 120 and the reinforcing layer 130 are stacked on the substrate. That is, the present invention is a coil component in which a laminate composed of the magnetic substrate 110, the insulating layer 120, and the reinforcing layer 130 is a unit element, and the laminate is a rectangular parallelepiped having a size of approximately 0403 .

Further, the magnetic substrate 110 also functions as a path for moving a magnetic flux generated when a current is applied.

Therefore, the magnetic substrate 110 may be made of any magnetic material, such as Fe ₂ O ₃ and Ni-based ferrite material containing NiO as a main component, Fe ₂ O ₃ , NiO, and ZnO as the main components so long as a predetermined inductance can be obtained A Ni-Zn ferrite material, and a Ni-Zn-Cu ferrite material containing Fe ₂ O ₃ , NiO, ZnO, and CuO as a main component. In addition, high modulus can be realized by sintering these materials in a high temperature atmosphere.

An insulating layer 120 is formed on the magnetic substrate 110 and a coil conductor 140 is formed in the insulating layer 120.

The coil conductor 140 is a coil-shaped metal wiring formed on a plane, and is formed of a metal conductor such as Ag, Pd, Al, Ni, Ti, (Au), copper (Cu), or platinum (Pt).

The coil conductor 140 may have a multilayer structure, and the electrical connection between the layers may be made via the via 141.

Here, the coil conductors 140 of each layer may be electromagnetically coupled to each other by forming individual coils such as a primary coil 140a and a secondary coil 140b. Alternatively, as shown in the drawing, the electromagnetic coupling may be formed as a so-called coincident coil structure in which the primary coil 140a and the secondary coil 140b are alternately wired in one layer.

As described above, the coil component 100 of the present invention has the primary coil 140a and the secondary coil 140b electromagnetically coupled to each other, so that the primary coil 140a and the secondary coil 140b are magnetized in the same direction When the current is applied, the magnetic flux is reinforced to increase the common mode impedance. When the current flows in the opposite direction, the magnetic fluxes are canceled each other to operate as a common mode filter in which the differential mode impedance decreases.

The insulating layer 120 is formed to surround the coil conductor 140.

Specifically, the insulating layer 120 is formed by first forming a base layer that secures insulation with the magnetic substrate 110 and suppresses surface irregularities of the magnetic substrate 110 to provide flatness, and a coil conductor 140 is formed thereon. And a build-up layer for covering the build-up layer. However, the boundaries between layers in the high-temperature and high-pressure lamination process can be unified as shown in the drawings without being distinguished.

As described above, the insulation layer 120 functions to secure insulation between wires by embedding the coil conductor 140, and to protect the coil conductor 140 from external environments such as moisture and heat. Therefore, as the constituent material of the insulating layer 120, a polymeric resin such as an epoxy resin, a phenol resin, a urethane resin, a silicone resin, a polyimide resin and the like having not only insulation but also excellent heat resistance and moisture resistance can be used.

However, since such a polymer resin generally has a large coefficient of thermal expansion (CTE) of 50 ppm / K or more, warpage may occur during a high-temperature heat treatment process. In addition, since the magnetic substrate 110 made of sintered ferrite exhibits a low thermal expansion coefficient (CTE) of about 8 to 10 ppm / K as opposed to the insulating layer 120, the thermal expansion coefficient (CTE) Lifting may occur at the interface between the magnetic substrate 110 and the insulating layer 120.

In order to miniaturize the product, the thickness of the magnetic substrate 110 is made thin or the ferrite member 130 is not provided with a separate ferrite member in order to realize a high attenuation characteristic. do.

That is, the reinforcing layer 130 is provided on the insulating layer 120 and has a lower thermal expansion coefficient (CTE) than the insulating layer 120. The reinforcing layer 130 functions as a stiffener that mitigates CTE mismatch between the magnetic substrate 110 and the insulating layer 120 and prevents warping of the insulating layer 120 together with the magnetic substrate 110. [ do.

Specifically, the thermal expansion coefficient (CTE) of the reinforcing layer 130 may be set within a range of 20 to 30 ppm / K. If the thermal expansion coefficient (CTE) of the reinforcing layer 130 is set to be too low, the insulating layer 120 may have a lower thermal expansion coefficient than that of the magnetic substrate 110. In this case, ) And the enhancement layer 130 may result in a CTE mismatch. Therefore, it is preferable that the reinforcing layer 130 is formed of a material having a coefficient of thermal expansion (CTE) within the above range.

The reinforcing layer 130 may be formed of a non-magnetic material, specifically, a dielectric material having a dielectric loss tangent of 0.3 or less. For example, an epoxy resin, a phenol resin, a urethane resin, a silicone resin, a polyimide resin, or other polymer resin may be used as an optimum material constituting the reinforcing layer.

Accordingly, magnetic loss does not occur even when a magnetic flux generated when a current is applied passes through the reinforcing layer 130. As a result, a high attenuation characteristic can be realized even in a high frequency band.

A non-magnetic inorganic filler 131 may be dispersed and contained in the reinforcing layer 130 and the CTE of the reinforcing layer 130 may be controlled through a content ratio of the inorganic filler 131.

In other words, the reinforcing layer 130 is an inorganic filler (131) having a coefficient of thermal expansion (CTE) of about the polymer resin and average 10ppm / K, for example, alumina (Al ₂ O _3), silica (SiO ₂₎ and titanium oxide (TiO ₂ The CTE of the reinforcing layer 130 can be lowered by increasing the content ratio of the inorganic filler 131. [

However, if an excessive amount of the inorganic filler 131 is contained, the specific gravity of the resin may be reduced to weaken the bonding strength between the reinforcing layer 130 and the insulating layer 120. Therefore, it is preferable to use an appropriate amount of the inorganic filler 131 .

An outer electrode 150 for electrical conduction to the outside is provided on the outer periphery of the insulating layer 120. That is, the external electrode 150 is formed to have a predetermined thickness and is electrically connected to the end of the coil conductor 140 through the bump electrode 151 in the insulating layer 120.

More specifically, the coil conductor 140 is composed of a primary coil 140a and a secondary coil 140b that are electromagnetically coupled. Therefore, the external electrode 150 is connected to both ends of the primary coil 140a, A pair of external electrodes 150 connected to the primary coil 140a and serving as an input and an output terminal of the primary coil 140a and a pair of external electrodes 150 connected to both ends of the secondary coil 140b, And a pair of external electrodes 150 functioning as a pair of electrodes. Each of the external electrodes 150 is disposed in the vicinity of each corner of the insulating layer 120 while being rotated clockwise or counterclockwise from the upper left corner of the upper portion of the insulating layer 120.

In this structure, the reinforcing layer 130 is inserted into the space between the external electrodes 150. That is, the reinforcing layer 130 is formed to have a thickness corresponding to that of the external electrode 150, so that only the upper surface of the external electrode 150 is exposed to the outside while the side surface of the external electrode 150 is surrounded by the reinforcing layer 130.

When the coil component 100 of the present invention is mounted on a substrate, the upper surface of the reinforcing layer 130 is provided as a mounting surface, and thus a solder ball is attached to the upper surface of the external electrode 150 exposed to the outside.

Since the reinforcing layer 130 is provided between the external electrodes 150, the present invention can prevent a solder bridge from being electrically short-circuited between the external electrodes 150 due to the solder liquid . If the soldering process is performed while all of the side surfaces of the external electrode 150 are opened without the reinforcing layer 130, the solder liquid flows into the empty space between the external electrodes 150, resulting in short failure.

As described above, the reinforcing layer 130 also functions as a shielding layer for insulating between the external electrodes 150 in addition to the function of alleviating the CTE deviation. This is because the gap between the external electrodes 150 becomes narrower The effect can be further exerted in the structure, and the SMT (Surface Mount Technology) mountability can be improved.

Table 1 below shows the SMT mounting performance and the warpage in the structures (Examples 1 to 3) in which the reinforcing layer 130 was formed by each size (Examples 1 to 3) and the structures (Comparative Examples 1 to 3) Data value.

Here, the SMT mountability shows that the number of the SMT mounts stably mounted without mounting the solder bridges when hundreds of specimens were mounted on the substrate, and the wiper strips were formed on the insulating layer after the reflow process at the center point of the insulating layer 120 120) is measured.

As shown in Table 1, in the case of Comparative Examples 1 to 3 in which the reinforcing layer 130 is not provided, the smaller the product is, the fewer the number of the products to be stably mounted. This is because the smaller the size of the product, the smaller the distance between the external electrodes 150 is. In addition, the wiper generated in the 0403 size increases approximately 6 times as compared with the 0806 size.

On the other hand, in the case of Examples 1 to 3 in which the reinforcing layer 130 is provided, all the hundred specimens are stably mounted regardless of the size, and in the case of warpage, compared with the case where the reinforcing layer 130 is not provided based on the 0403 size Which is approximately 1/10.

Although the external electrode 150 has been described as being provided as a bottom structure, the present invention may also provide a coil component in which the external electrode 150 is provided as a side structure. This will be described with reference to Fig. 4 below.

4 is a perspective view of a coil component according to another embodiment of the present invention.

4, a coil component 200 according to another embodiment of the present invention includes a magnetic substrate 210, an insulating layer 220, and a reinforcing layer 230 stacked in order from the bottom in the same manner as in the above- The structure becomes a basic element. Although not shown in the figure, a primary coil and a secondary coil which are electromagnetically coupled to each other inside the insulating layer 220 are installed as a multilayer structure or a co-coil structure.

Here, the materials of the magnetic substrate 210, the insulating layer 220, and the reinforcing layer 230, and the functions thereof are the same as those described above, and thus a detailed description thereof will be omitted.

Both ends of the primary coil and the secondary coil are exposed on the side surface of the insulating layer 220 and contact the outer electrode 250. That is, the external electrodes 250 are all composed of four terminals functioning as input and output terminals of the primary and secondary coils, and each of the external electrodes 250 includes the magnetic substrate 210 and the insulating layer 220, And a reinforcing layer 230, and is connected to an end portion of the first and second coils exposed to the outside.

Now, a method of manufacturing a coil part of the present invention will be described.

FIG. 5 is a flowchart sequentially illustrating a method of manufacturing a common mode filter according to the present invention. In the method of manufacturing a coil component of the present invention, first, a magnetic powder of Ni ferrite, Ni- Zn ferrite, or Ni- The magnetic substrate 110 is prepared by sintering under a predetermined condition (S100).

Next, the step of forming the insulating layer 120 on which the coil conductor 140 is embedded is formed on the magnetic substrate 110 (S110).

To this end, first, an insulating material is coated on the upper surface of the magnetic substrate 110 using a conventional coating method such as spin coating, and a coil conductor 140 is plated thereon.

As the plating method of the coil conductor 140, a conventional plating process known in the art, such as SAP (Semi-Additive Process), MSAP (Modified Semi-Additive Process) or Subtractive When a coil conductor 140 of one layer is formed, an insulating material covering the coil conductor 140 is coated. This process is repeated for the required number of coil conductors 140 and then fired to form the insulating layer 120 in which the coil conductor 140 is buried.

Next, external electrodes 150 having a predetermined thickness are formed according to the above-described plating method (S120), and the mixed paste prepared by milling the polymer resin and the inorganic filler 131 between the external electrodes 150 is filled and cured The coil component 100 of the present invention in which the reinforcing layer 130 is formed is finally completed (S130).

The foregoing detailed description is illustrative of the present invention. It is also to be understood that the foregoing is illustrative and explanatory of preferred embodiments of the invention only, and that the invention may be used in various other combinations, modifications and environments. That is, it is possible to make changes or modifications within the scope of the concept of the invention disclosed in this specification, the disclosure and the equivalents of the disclosure and / or the scope of the art or knowledge of the present invention. The foregoing embodiments are intended to illustrate the best mode contemplated for carrying out the invention and are not intended to limit the scope of the present invention to other modes of operation known in the art for utilizing other inventions such as the present invention, Various changes are possible. Accordingly, the foregoing description of the invention is not intended to limit the invention to the precise embodiments disclosed. It is also to be understood that the appended claims are intended to cover such other embodiments.

100: coil part according to the present invention
110: magnetic substrate
120: insulating layer
130: reinforced layer
131: Inorganic filler
140: coil conductor
150: external electrode

Claims

A magnetic substrate;
An insulating layer formed on the magnetic substrate and having a coil conductor formed therein; And
And a reinforcing layer provided on the insulating layer and having a thermal expansion coefficient smaller than that of the insulating layer,
Wherein the reinforcing layer comprises a mixture of a polymer resin and an inorganic filler, and the inorganic filler is any one selected from the group consisting of alumina (Al ₂ O ₃ ), silica (SiO ₂ ) and titanium oxide (TiO ₂ ) Lt;
Wherein the reinforcing layer has a thermal expansion coefficient ranging from 20 ppm / K to 30 ppm / K,
Coil parts.

The method according to claim 1,
And the thermal expansion coefficient of the reinforcing layer is larger than that of the magnetic substrate.

The method according to claim 1,
Wherein the reinforcing layer is formed of a non-magnetic material.

delete

The method according to claim 1,
The magnetic substrate is made of sintered ferrite.

The method according to claim 1,
Further comprising an external electrode provided on an outer periphery of the insulating layer and electrically connected to the coil conductor, wherein the reinforcing layer is inserted into a void space between the external electrodes.

The method according to claim 1,
Wherein the coil conductor comprises a primary coil and a secondary coil that are electromagnetically coupled.

A magnetic substrate;
An insulating layer formed on the magnetic substrate and having a coil conductor formed therein;
A reinforcing layer provided on the insulating layer and having a thermal expansion coefficient lower than that of the insulating layer; And
And an external electrode provided on a side surface of the multilayer body composed of the magnetic substrate, the insulating layer, and the reinforcing layer, and electrically connected to the end of the coil conductor exposed on the side surface of the insulating layer,
Wherein the reinforcing layer comprises a mixture of a polymer resin and an inorganic filler, and the inorganic filler is any one selected from the group consisting of alumina (Al ₂ O ₃ ), silica (SiO ₂ ) and titanium oxide (TiO ₂ ) Lt;
Wherein the reinforcing layer has a thermal expansion coefficient ranging from 20 ppm / K to 30 ppm / K,
Coil parts.

10. The method of claim 9,
And the thermal expansion coefficient of the reinforcing layer is larger than that of the magnetic substrate.

10. The method of claim 9,
Wherein the reinforcing layer is formed of a non-magnetic material.

delete

10. The method of claim 9,
The magnetic substrate is made of sintered ferrite.

Preparing a magnetic substrate;
Forming an insulating layer on the magnetic substrate on which a coil conductor is formed; And
And forming a reinforcing layer on the insulating layer,
In the step of forming the reinforcing layer, a mixed paste of a polymer resin and an inorganic filler is filled and cured,
The inorganic filler may be any one selected from the group consisting of alumina (Al ₂ O ₃ ), silica (SiO ₂ ), and titanium oxide (TiO ₂ )
Wherein the reinforcing layer has a thermal expansion coefficient ranging from 20 ppm / K to 30 ppm / K,
Method of manufacturing coil parts.

delete

16. The method of claim 15,
Forming an outer electrode on the outer surface of the upper portion of the insulating layer before forming the reinforcing layer, filling a void space between the outer electrodes with a mixed paste of a polymer resin and a non-magnetic filler, Of the coil component.